criminal psychology-第102章

按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！


longer　pay　any　attention　to　them。　‘‘I　find　it　difficult；''　says　Lipps；＇1＇　‘‘to　believe　that　the　oven　which　stands　in　the　corner　of　the　room　does　not　look　larger　than　my　hand　when　I　hold　it　a　foot　away　from　my　eyes；　or　that　the　moon　is　not　larger　than　the　head　of　a　pin；　which　I　look　at　a　little　more　closely。。。。　We　must　not　forget　how　we　are　in　the　custom　of　comparing。　I　compare　hand　and　oven；　and　I　think　of　the　hand　in　terms　of　the　oven。''　That　is　because　we　know　how　large　the　hand　and　the　oven　are；　but　very　often　we　compare　things　the　sizes　of　which　we　do　not　know；　or　which　we　can　not　so　easily　get　at；　and　then　there　are　many　extraordinary　illusions。


＇1＇　Die　Grundtatsachen　des　Seelenlebens。　Bonn　1883。


In　connection　with　the　cited　incident　of　the　estimation　of　the　　moon's　diameter；　there　is　the　illusion　of　Thomas　Reid　who　saw　that　the　moon　seemed　as　large　as　a　plate　when　looked　at　with　the　unhampered　eye；　but　as　large　as　a　dollar　when　looked　at　through　a　tube。　This　mistake　establishes　the　important　fact　that　the　size　of　the　orifice　influences　considerably　the　estimation　of　the　size　of　objects　seen　through　it。　Observations　through　key…holes　are　not　rarely　of　importance　in　criminal　cases。　The　underestimations　of　sizes　are　astonishing。


｛illust。　caption　=　FIG。　1。｝

｛illust。　caption　=　FIG。　2。｝


Arial　perspective　has　a　great　influence　on　the　determination　of　these　phenomena；　particularly　such　as　occur　in　the　open　and　at　great　distances。　The　influence　is　to　be　recognized　through　the　various　appearances　of　distant　objects；　the　various　colors　of　distant　mountains；　the　size　of　the　moon　on　the　horizon；　and　the　difficulties　which　arial　perspective　offers　painters。　Many　a　picture　owes　　its　success　or　failure　to　the　use　of　arial　perspective。　If　its　influence　is　significant　in　the　small　space　of　a　painting；　the　illusions　in　nature　can　easily　become　of　enormous　significance；　particularly　when　extremes　are　brought　together　in　the　observations　of　objects　in　unknown　regions。　The　condition　of　the　air；　sometimes　foggy　and　not　pellucid；　at　another　time　particularly　clear；　makes　an　enormous　difference；　and　statements　whether　about　distance；　size；　colors；　etc。；　are　completely　unreliable。　A　witness　who　has　several　times　observed　an　unknown　region　in　murky　weather　and　has　made　his　important　observation　under　very　clear　skies；　is　not　to　be　trusted。

An　explanation　of　many　sensory　illusions　may　be　found　in　the　so…called　illusory　lines。　They　have　been　much　studied；　but　Zllner＇1＇　has　been　the　first　to　show　their　character。　Thus；　really　quite　parallel　lines　are　made　to　appear　unparallel　by　the　juxtaposition　of　inclined　or　crossing　lines。　In　figures　1　and　2　both　the　horizontal　lines　are　actually　parallel；　as　may　be　determined　in　various　ways。


＇1＇　Poggendorf's　Annelen　der　Physik；　Vol。　110；　p。　500；　114；　587；　117；　477。


The　same　lines　looked　at　directly　or　backwards　seem；　in　Fig。　1；　convex；　in　Fig。　2　concave。


｛illust。　caption　=　FIG。　3。｝


Still　more　significant　is　the　illusion　in　Fig。　3；　in　which　the　convexity　is　very　clear。　The　length；　etc。；　of　the　lines　makes　no　difference　in　the　illusion。　

On　the　other　hand；　in　Fig。　4　the　diagonals　must　be　definitely　thicker　than　the　parallel　horizontal　lines；　if　those　are　to　appear　not　parallel。　That　the　inclination　is　what　destroys　the　appearance　of　parallels　is　shown　by　the　simple　case　given　in　Fig。　5；　where　the　distance　from　A　to　B　is　as　great　as　from　B　to　C；　and　yet　where　the　first　seems　definitely　smaller　than　the　second。

Still　more　deceptive　is　Fig。　6　where　the　first　line　with　the　angle　inclined　inwards　seems　incomparably　smaller　than　the　second　with　the　angle　inclined　outwards。


｛illust。　caption　=　FIG　4。｝



All　who　have　described　this　remarkable　subject　have　attempted　to　explain　it。　The　possession　of　such　an　explanation　might　put


｛illust。　caption　=　FIG。　5。｝

｛illust。　caption　=　FIG。　6。｝


us　in　a　position　to　account　for　a　large　number　of　practical　difficulties。　But　certain　as　the　facts　are；　we　are　still　far　from　their　_*why_　and　_*how_。　We　may　believe　that　the　phenomenon　shown　in　Figs。　1　and　2　appears　when　the　boundaries　of　a　field　come　straight　up　to　a　street　with　parallel　sides；　with　the　result　that　at　the　point　of　meeting　the　street　seems　to　be　bent　in。　Probably　we　have　observed　this　frequently　without　being　aware　of　it；　and　have　laid　no　particular　stress　on　it；　first　of　all；　because　it　was　really　unimportant；　and　secondly；　because　we　thought　that　the　street　was　really　not　straight　at　that　point。

In　a　like　manner　we　may　have　seen　the　effect　of　angles　as　shown　in　Figs。　5　and　6　on　streets　where　houses　or　house…fronts　were　built　cornerwise。　Then　the　line　between　the　corners　seemed　longer　or　shorter；　and　as　we　had　no　reason　for　seeking　an　accurate　judgment　　we　paid　no　attention　to　its　status。　We　simply　should　have　made　a　false　estimate　of　length　if　we　had　been　required　to　judge　it。　It　is　also　likely　that　we　may　have　supposed　an　actual　or　suppository　line　on　the　side　of　the　gables　of　a　house　enclosed　by　angles　of　the　gables；　to　be　short；but　until　now　the　knowledge　of　this　supposition　has　had　no　practical　value。　Nevertheless；　the　significance　of　these　illusions　should　not　be　underestimated。　They　mean　most　of　all　the　fact　that　we　really　can　be　much　deceived；　even　to　the　degree　of　swearing　to　the　size　of　a　simple　thing　and　yet　being　quite　innocently　mistaken。　This　possibility　shows；　moreover；　that　the　certainty　of　our　judgment　according　to　sensible　standards　is　inadequate　and　we　have　no　way　of　determining　how　great　this　inadequacy　is。　We　have　already　indicated　that　we　know　only　the　examples　cited　by　Zllner；　Delboeuf　and　others。　It　is　probable　that　they　were　hit　upon　by　accident　and　that　similar　ones　can　not　be　discovered　empirically　or　intentionally。　Hence；　it　may　be　assumed　that　such　illusions　occur　in　great　number　and　even　in　large　dimensions。　For　example；　it　is　known　that　Thompson　discovered　his　familiar　‘‘optical　circle　illusion''　（six　circles　arranged　in　a　circle；　another　in　the　middle。　Each　possesses　bent　radii　which　turn　individually　if　the　whole　drawing　is　itself　turned　in　a　circle）　by　the　accident　of　having　seen　the　geometrical　ornament　drawn　by　a　pupil。　Whoever　deals　with　such　optical　illusions　may　see　very　remarkable　ones　in　almost　every　sample　of　ladies'　clothes；　particularly　percale；　and　also　in　types　of　carpets　and　furniture。　And　these　are　too　complicated　to　be　described。　In　the　course　of　time　another　collection　of　such　illusions　will　be　discovered　and　an　explanation　of　them　will　be　forthcoming；　and　then　it　may　be　possible　to　determine　how　our　knowledge　of　their　existence　can　be　turned　to　practical　use。

Practical　application　is　easier　in　the　so…called　inversion　of　the　visual　object。　Fig。　7　shows　the　simplest　case　of　itthe　possibility　of　seeing　the　middle　vertical　line　as　either　deeper　or　higher　than　the　others。　In　the　first　instance　you　have　before　you　a　gutter；


｛illust。　caption　=　FIG。　7。｝

｛illust。　caption　=　FIG。　8。｝


in　the　second　a　room。　Similar　relations　are　to　be　observed　in　the　case　of　a　cube　in　which　the　corner　a　may　be　seen　as　either　convex　or　concave　according　as　　you　think　it　behind　or　before　the　background　of　the　angles　from　which　_a_　proceeds。　It　is　still　clearer　when；　in　a　rhomboid；　the　line　_XY_　is　drawn。　Then　_x_　or　_y_　may　be　seen　alternately　as　nearer　or　further　and　the　figure　can　thereby　be　brought　into　a　different　position。　（Fig。　9。）　Done　once　it　may　be　repeated　voluntarily。

There　are　many　practical　examples　of　these　illusions。　Sinsteden　saw　one　evening　the　silhouette　of　a　windmill　against　a　luminous　background。　The　arms　seemed　now


｛illust。　caption　=　FIG。　9。｝


to　go　to　the　right；　now　to　the　leftclearly　because　he　did　not　make　out　the　body　of　the　mill　and　might　equally　assume　that　he　saw　it　from　the　front　or　from　the　rear；　the　wheels　going　toward　the　right　in　the　first；　and　toward　the　left　in　the　other　case。　An　analogous　case　is　cited　by　Bernstein。　If　（Fig。　10）　the　cross　made　of　the　thin　lines　stand　for　the　bars　of　a　weather　vane　and　the　heavy　lines　represent　the　weather　vane　itself；　it　may　be　impossible　under　the　conditions　of　illumination　for　an　eye　looking　from　N　to　distinguish　whether　the　weather　vane　points　NE　or　SW；　there　is　no　way　of　determining　the　starting　point　of　motion。　All　that　can　certainly　be　said　is　that　the　weather　vane　lies　between　NE　and　SW　and　that


｛illust。　caption　=　FIG。　10。｝


its　angle　is　at　the　crossing　of　the　two　lines；　but　the　direction　in　which　its　heads　point　can　not　be　determined　at　even　a　slight　distance。　Both　forms　of　this　illusion　may　occur　in　a　criminal　trial。　If　once　a　definite　idea　of　some　form　of　order　has　been　gained；　it　is　not　abandoned　or　doubted；　and　is　even　sworn　to。　If　asked；　for　example；　whether　the　mill…wheel　moved　right　or　left；　the　observer　will　consider　hardly　one　time　in　a　hundred　whether　there　might　not　have　been　an　optical　illusion。　He　will　simply　assure　　us　that　the　thing　was　as　he　thinks　he　saw　it；　and　whether　he　saw　it　correctly　is　purely　a　matter　of　luck。

To　all　these　illusions　may　be　added　those　which　are　connected　with　movement　or　are　exposed　by　movement。　During　the　movement　of　certain　bodies　we　can　distinguish　their　form　only　under　definite　conditions。　As　their　movement　increases　they　seem　shorter　in　the　direction　of　movement　and　as　it　decreases　they　seem　broader　than　normally。　An　express　train　with　many　cars　seems　shorter　when　moving　directly　near　us；　and　rows　of　marching　men　seem　longer。　The　illusion　is　most　powerful　when　we　look　through　a　stationary　small　opening。　The　same　thing　occurs　when　we　move　quickly　past　bodies；　for　this　makes　them　seem　very　short　as　we　go　by。

Of　such　cases　sense…illusion　does　not　constitute　an　adequate　explanation；　it　must　be　supplemented　by　a　consideration　of　certain　inferences　which　are；　in　most　instances；　comparatively　complex。＇1＇　We　know；　e。　g。；　that　objects　which　appear　to　us　unexpectedly　at　night；　particularly　on　dark；　cloudy　nights；　seem　inordinately　magnified。　The　process　is　here　an　exceedingly　complex　one。　Suppose　I　see；　some　cloudy　night；　unexpectedly　close　to　me　a　horse　whose　environment；　because　of　the　fog；　appears　indistinct。　Now　I　know　from　experience　that　objects　which　appear　from　indistinct　environments　are　as　a　rule　considerably　distant。　I　know；　further；　that　considerably　distant　objects　seem　much　smaller；　and　hence　I　must　assume　that　the　horse；　which　in　spite　of　its　imaginary　distance　appears　to　retain　its　natural　size；　is　really　larger　than　it　is。　The　train　of　thought　is　as　follows：　‘‘I　see　the　horse　indistinctly。　It　seems　to　be　far　away。　It　is；　in　spite　of　its　distance；　of　great　size。　How　enormous　it　must　be　when　it　is　close　to　me！''　Of　course　these　inferences　are　neither　slow　nor　conscious。　They　occur　in　reflection　with　lightning…like　swiftness　and　make　no　difference　to　the　certainty　of　the　instantaneous　judgment。　Hence　it　is　frequently　very　difficult　to　discover　the　process　and　the　mistake　it　contains。


＇1＇　W。　Larden：　Optical　Illusion。　Nature　LXIII；　372　（1901）。


If；　however；　the　observer　finds　an　inexplicable　hiatus　in　an　event　he　happens　to　notice；　he　finds　it　strange　because　unintelligible。　In　this　way　is　created　that　notion　of　st